Byte-code - Definition with links to related topics. [FOLDOC, open content]
Bytecode - Growing article, with links to many related topics. [Wikipedia, open content, GNU FDL]
Parrotcode - Home of Parrot Virtual Machine, made for dynamic languages, originally a target for Perl 6 compiler, hosts many language implementations in varied stages of completion: Tcl, Javascript, Ruby, Lua, Scheme, PHP, Python, Perl 6, APL, .NET. Open source.